
// 单词首字母转大写
export function toUpperCaseWord( val ) {
  if ( !val ) return ''
  return val.toLowerCase().replace( /( |^)[a-z]/g, L => L.toUpperCase() )
}

/**
 * Parse the time to string
 * @param {(Object|string|number)} time
 * @param {string} cFormat
 * @returns {string | null}
 */
export function parseTime( time, cFormat ) {
  if ( arguments.length === 0 || !time ) {
    return null
  }
  const format = cFormat || '{y}-{m}-{d} {h}:{i}:{s}'
  let date
  if ( typeof time === 'object' ) {
    date = time
  } else {
    if ( typeof time === 'string' ) {
      if ( /^[0-9]+$/.test( time ) ) {
        // support "1548221490638"
        time = parseInt( time )
      } else {
        // support safari
        // https://stackoverflow.com/questions/4310953/invalid-date-in-safari
        // eslint-disable-next-line prefer-regex-literals
        time = time.replace( new RegExp( /-/gm ), '/' )
      }
    }

    if ( typeof time === 'number' && time.toString().length === 10 ) {
      time = time * 1000
    }
    date = new Date( time )
  }
  const formatObj = {
    y : date.getFullYear(),
    m : date.getMonth() + 1,
    d : date.getDate(),
    h : date.getHours(),
    i : date.getMinutes(),
    s : date.getSeconds(),
    a : date.getDay()
  }
  const time_str = format.replace( /{([ymdhisa])+}/g, ( result, key ) => {
    const value = formatObj[key]
    // Note: getDay() returns 0 on Sunday
    if ( key === 'a' ) {
      return ['日', '一', '二', '三', '四', '五', '六'][value]
    }
    return value.toString().padStart( 2, '0' )
  } )
  return time_str
}

/**
 * @param {number} time
 * @param {string} option
 * @returns {string}
 */
export function formatTime( time, option ) {
  if ( ( '' + time ).length === 10 ) {
    time = parseInt( time ) * 1000
  } else {
    time = +time
  }
  const d = new Date( time )
  const now = Date.now()

  const diff = ( now - d ) / 1000

  if ( diff < 30 ) {
    return '刚刚'
  } else if ( diff < 3600 ) {
    // less 1 hour
    return Math.ceil( diff / 60 ) + '分钟前'
  } else if ( diff < 3600 * 24 ) {
    return Math.ceil( diff / 3600 ) + '小时前'
  } else if ( diff < 3600 * 24 * 2 ) {
    return '1天前'
  }
  if ( option ) {
    return parseTime( time, option )
  } else {
    return d.getMonth() + 1 + '月' + d.getDate() + '日' + d.getHours() + '时' + d.getMinutes() + '分'
  }
}

/**
 * @param {Function} func
 * @param {number} wait
 * @param {boolean} immediate
 * @return {*}
 */
export function debounce(func, wait, immediate) {
  let timeout, args, context, timestamp, result

  const later = function() {
    // 据上一次触发时间间隔
    const last = +new Date() - timestamp

    // 上次被包装函数被调用时间间隔 last 小于设定时间间隔 wait
    if (last < wait && last > 0) {
      timeout = setTimeout(later, wait - last)
    } else {
      timeout = null
      // 如果设定为immediate===true，因为开始边界已经调用过了此处无需调用
      if (!immediate) {
        result = func.apply(context, args)
        if (!timeout) context = args = null
      }
    }
  }

  return function(...args) {
    context = this
    timestamp = +new Date()
    const callNow = immediate && !timeout
    // 如果延时不存在，重新设定延时
    if (!timeout) timeout = setTimeout(later, wait)
    if (callNow) {
      result = func.apply(context, args)
      context = args = null
    }

    return result
  }
}


/**
 * This is just a simple version of deep copy
 * Has a lot of edge cases bug
 * If you want to use a perfect deep copy, use lodash's _.cloneDeep
 * @param {Object} source
 * @returns {Object}
 */
export function deepClone(source) {
  if (!source && typeof source !== 'object') {
    throw new Error('error arguments', 'deepClone')
  }
  const targetObj = source.constructor === Array ? [] : {}
  Object.keys(source).forEach(keys => {
    if (source[keys] && typeof source[keys] === 'object') {
      targetObj[keys] = deepClone(source[keys])
    } else {
      targetObj[keys] = source[keys]
    }
  })
  return targetObj
}

